Australian media outlet quotes source familiar with case as saying that Israel told Australian officials about the 2010 arrest.

Israel notified Australian officials of Ben Zygier’s arrest immediately
after he was detained, an Australian news agency reported.

Australia’s
Fairfax Media quoted a “well-placed source familiar with the case” as
saying Israeli intelligence had told Australian officials about the 2010
arrest of Zygier, a dual Australian-Israeli citizen dubbed Prisoner X.
Zygier committed suicide later that year while in prison in Israel and
is alleged to have worked with the Mossad.

Fairfax
Media's former Middle East correspondent, Jason Koutsoukis, said he had
been tipped off by an ''Australian intelligence source'' in October
2009 about concerns that Zygier may have been facilitating the use of
Australian passports by Israeli spies. He then interviewed Zygier, who
denied the allegation. A week after their last conversation, Zygier was
imprisoned.